Federer: Tim will push me at Wimbledon

Roger Federer believes Tim Henman will be one of his chief rivals as he bids to retain his Wimbledon crown.

Federer is keen to bounce back after his semi-final defeat by eventual champion Rafael Nadal at the French Open - the only Grand Slam event the world No1 has not won - and is looking forward to returning to London.

But the Swiss star, who is preparing for Wimbledon at the Gerry Weber Open title in Halle, expects a tough challenge from the British No1. The 23-year-old said: "I consider Tim Henman always a favourite to win the tournament, especially after getting better and better in recent years.

"I feel he has raised his baseline game which gives him an additional option even though he will pursue his net attacks on grass.

"But now he can keep up with the other players from the baseline and that makes him more dangerous. Andy Roddick is also a big favourite after last year's final and Sebastien Grosjean after two visits to the semi-finals. And Lleyton Hewitt will be very strong. He's always in good form for the big tournaments."

Federer has won six titles this year - at Hamburg, Indian Wells, Miami, Doha, Dubai and Rotterdam - but admits now is the time to prove he is worthy of his ranking.

"I have had a super season even without winning a Grand Slam but now it's that time of the year where I need to make sure I defend my Wimbledon title and stay No1," he said.